Electric arc furnace.



0.1. S. PLATOUv ELECTRIC AR C FURNACE. APPLICATION FILED JUNE 2,1916.

1,241,655. Patented 001;. 2, 1917.

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OLAT'E JOHAN STOUD PLATOU, F CHRISTIANIA, NORWAY, ASSIGNOR TO NORSKHYDRO- ELEKI'BISK KVAELSTOFAKTIESELSKAB, 0F CHRISTIANIA, NORWAY.

nLnc'rRIc-Aac FURNACE.

nee-Less.

;ments in Electric-Arc Furnaces; and I do hereby declare the tollowingto be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which it appertains to make anduse the same, reference being had to the accompanying drawings, and toletters or figures of reference marked thereon, which form a part ofthis specification.

In electric arc furnaces the reaction chamher is generallybuilt offire-brick ,masonry and surrounded by.a shell of iron or other metal inorder to prevent gas leakages through the porous furnace material. Ithas already been proposed to place this metal shell at some distancefrom the wall of the reaction chamber and to use the space between' as'conduit for the gas supply ,of'the furnace) According to the presentinven-' tion the metal shell is constituted by the magnetic material ofthe furnace in such a manner, that the part of the magnet constructionuniting the magnet poles of each side of the furnace is given the shapeof a bell or hemisphere.

' The. annexed drawing illustrates .the invention, as used-inlcomiectionwith a furnace-- of the BirkelaIid-Eyde type.

The drawing embodies a section, through the spherical 0r bell-shapedmagnet arrangement a1, a, which may be cast in one piece of iron orsteel or built up of separate parts in. any suitable manner, andeventually some of the parts may be of non-magnetic material. The shellconstruction bears magnet poles b, the number, shape and position ofwhich are not essential for the invention.

To render the drawing fully explanatory also the furnace chamber 0 withthe surrounding brickwork (Z is shown, As to the magnet coils e thearrangement, already kno wn heretofore, is shown, in which the air, byoutside pressure or by suction from the furnace chamber, is supplied tothe latbefore ter through the apertures f and is caused to pass themagnet coils for cooling the same entering the reaction chamber throughthe perforated. brickwork. The electrodes in this type of furnace aregenerally mounted in a plane perpendicular to Specification of LettersPatent.

Patented Jet. 2, rear.

Application filed June 2, 1916. Serial No. 101,425.

the axis of the magnets. I One of such electrodes is shown at iprojecting from its 1nsulatiug piece 72.

I As above mentioned the magnet construction may be built up of sctionsin any suit- .able manner, being fo'rinstance subdivided along thecenter line 9' g. It is however very advantageous to arrange thpdivisions in such a manner thatthe brickwork may easily be laid open forinspection. This very important advantage, which the constructionshitherto used are lacking, may for instance be realized by making themagnet poles with their flanges 2, that form part of thecasingdetachable at h'. As a matter of course the furnace shell must beprovided with necessary apertures for the gas currents, electrodes, etc.I

- For the purpose of regu'lating the distance of the poles, the lattershould be dis lace: i

able longitudinally. This may be e ected either by interposingsuitableadjusted metal pieces at it or in the manner that the pole b ismade lengthwise adjustable in the shell a, as is by way of examplepointed out on the right hand-of the drawing, For variation of thespreading effect, on the. flame the, in-

tensity of the magnetic field may also be variedin themanner that aninner part b and an outer )art I) of the pole core are made displacea leto one another, an arrangement that is likewise indicated on the rightside of the figure. As illustrated the inner part b is adjustablerelatively to the outer part b.

As compared with constructions hitherto known, where the magnet body andthe air shell of the furnace are independent of one another, the abovedescribed arrangement offers very important advantages;

So the whole building up of the furnace is considerably simplified, asthe magnet construction substitutes the metal covering otherwiserequired. The sides of the furnace. (magnet bells a a) which alreadywith regard to the magnetic conductivity must be of considerablethickness are utilized for enhancing the mechanical stability of thefurnace. In this way the disagreeable noise thatis so characteristic ofthe furnaces hitherto used is to a great extent eliminated105 formadapts the furnace immediately for thg 11.0

mg. In fact ing constituted use of high gas pressures. tlie same timethe air space of the shell is enlarged to such an extent that a veryfavorable buifer elfect is obtained, which is likewise. conducive .to

5 quiet burn 11g of the flame and regular working of the furnace.Finally it is obvious that alsovthe present construction utilizes thealready known effect ofv gas currents m the space between the reactionchamber and the metal covering, as to prevention of puncstructionrespectively with due reference to the special conditions of the furnacein question. The shell construction above described is by no meansboundto the manner of gas conduction indicated by the drawit isapplicable 'to normal Birkeland-Eyde furnaces of any modification beingespecially useful for large furnaces.

Iclaim- 1. In an electric arc furnace having a magnetically spreadflame; a reaction chamber surrounded by a metal shell, said shellconstituting part of the magnetic construction uniting the magneticpoles.

2. In an electric arc furnace having a magnetically spread flame; areaction chamber surrounded by a metalshell, said shell beby the magnetconstruction and forming a free space between the Wall of the reactionchamber and said metal shell.

3. In an electric arc furnace having a mag netically. spread flame; areaction chamber surrounded by a shell, said shell being concoplel ofthis patient may be obtained for five cents each, by addressing thebetween them, the novelty which comprises extending the metallic magnetcores in the form of a casing for said chamber, thereby utilizing saidextended metallic portion both as a casing for said chamber and as a me-ellic portion of the magnetic circuit between the opposed magnets.

5. In an electric furnace having a pair I of magnets in operativerelation to a furnace chamber between them, a metallic casing for saidchamber forming air between the casing and chamber, said casing havingsuitable openings,- therein for said magnets. closing-plates forsaidopenings, each closing plate forming a flange on the metallic coreof a magnet.

6. In an electric furnace having a air of magnets in operative relationto a t chamber between them," a metallic casing for said "chamberforming air spaces between said casing and chamber, said casing being intwo dome-shaped portions, each portion having magnet, and a closure foreach opening constituted by a flange on the magnet core.

In testimony that I claim the foregoing as my invention, I have signedmy name in presence of two subscribing witnesses.

l our JOHAN ST'OUD PLATOU.

Witnesses: v

T. SoHJoLBERe HnNnIKsEN, HARAL V. MEYER.

Commissioner or mm,

Washington, 3H3." A

spaces an openlng therein fora

